Become one with your modeling tool

We just wrapped up our Banff workshop, with about the best weather imaginable for a mountain autumn. Chilly mornings but gorgeous sun and highs in the 20s (Celsius) all week.

It was great to see some of you there. Believe it or not, I always learn a tonne from talking with you and watching how you work. I walk away from workshops feeling invigorated and excited about the potential the future holds.

There are often some embarrassing moments. Like when View Slice Information crashed within the first hour or two of the workshop, on the presenter’s computer as well as many of the attendees’. We’ve been fighting that crash for months and thought we had it licked, but apparently not.

There’s a happy ending to that story, however. As a result of watching it happen to a whole roomful of people, by the end of the next day I was able to find the bad line of code and finally fix it. I think for real this time! The next release (7.13–which we just released yesterday) includes this fix as well as a host of other improvements.

This was our first time to offer an optional fourth day. The dynamics of that last day were much different than the first three. The smaller group and more casual sessions allowed us to have more informal discussions and get to know each others’ backgrounds a bit more.

Grokking GeoStudio was launched a year ago today. I’d like to take a few moments to reminisce about the past year, and think ahead toward the coming one.

Last Year

This whole blogging thing was an experiment from the beginning. I had a couple of goals:

Provide help for GeoStudio users to learn how to use the software, with a different focus than the manuals and online help.

Get a better feel personally for how our software is being used “in the real world” through feedback from readers.

Be a friendly personal face to GEO-SLOPE.

I tried to blog weekly, and although I wasn’t that regular, I did (coincidentally?!) end up writing 52 posts over the year!

Did I meet my goals?

Much of what I wrote about is not discussed in the online help or the engineering books, or is mentioned but is hard to find. With the recent changes to the blog categories and layout, I hope that those 52 gems will be easier for newcomers to find, so the blog can be used as a bit of a reference tool.

I receive several emails or comments a month, and from those I do get a small feel for how the software is being used. A big thank you to everyone who felt the freedom to write! This is an area I’d like to improve on next year–I would love to see more feedback, especially comments left on the blog, and even to have readers responding to other reader’s comments.

I’ll leave #3 to you to decide!

Some interesting statistics (at least to me!):

52 posts;

12 comments from readers, and a similar number of emails (all of which I respond to);

Around 48 regular readers, and growing slowy, 37 of whom subscribe by email, the rest using RSS readers; The biggest jumps in subscribers come when the blog gets mentioned in a Direct Contact newsletter, especially when it’s the main article.

The web site has been visited from 90 countries, but only gets about ten visits a day.

Next Year

Before starting to blog I wrote up a list of topics I wanted to write on, just to make sure there was enough to keep me going. I’m mostly through that list now, but from the comments, from tech support we do, and from discussions at the Banff Workshop that just finished, I feel I have plenty more to keep this blog going another year.

To spice things up a bit, though, I’d like to have more guest bloggers this year. It would be nice to hear some tricks from people who use the software regularly. Do any of you have something you’d be willing to share on this blog? Email me privately (hekman at geo-slope dot com) to discuss.

I’d also like to stretch my limits a bit and write about a few more engineering-related topics, like the Multi-Stage Rapid Drawdown article. Those are harder for me to write, I normally have to sit down for a lesson with one of our engineers, but they are useful things for me to know and they are obviously topics you are wanting addressed. If you have topic suggestions, please let me know by leaving a comment.

But mostly I intend this year to focus where my strengths lie, which is the user interface. I’m going to take a look at DXF issues, dig deeper into functions and graphs, take a stab at plug-ins, and as much as possible help you to get past the software and focus on your modeling.

In an attempt to make this blog be more useful, I’ve updated the layout, hoping to make it easier to find what you need.

One change in particular I’d like to point out:

The Categories have been rearranged, around commands, objects or concepts in the software. That should help you if you don’t follow the blog regularly, or you only ran across it recently. If you’re struggling to understand functions you can click on the Functions category and immediately see everything I’ve written about functions.

Summer is definitely over here in Calgary, with temperatures dipping and leaves changing colour. When our workshop is over next week I will be getting back into serious blogging mode again and try to bring you a new tip every week.

As always, if you have comments, suggestions or questions, please leave a comment or email me.

I hope your summers have been going well (or your winter–do I have any readers from the southern hemisphere?). This summer we’ve enjoyed beautiful weather here in Calgary, which has allowed me to rack up 800 km on my bike commuting to work. Woohoo!

I’m going to take a short blogging break. Grokking GeoStudio will be on holidays for the next couple of weeks, but I’ll be back in time to celebrate Grokking’s first anniversary, September 19th!

Will any of you be attending our annual workshop in Banff this year? September 15-18. Look me up, I’d love to chat with you face to face. If you haven’t signed up yet you’ll have to wait for next year–the workshop is full and the waiting list already a mile long.

We have a love-hate relationship with FLEXlm, the licensing utility that is responsible for those USB dongles you have to plug in before you can run GeoStudio.

On the one hand it’s annoying to have that dongle to keep track of, and a big pain if the automatic license renewal doesn’t work for some reason. But the nicer side is that it allows you to buy different types of licenses to better fit the way you want to use the software.

Even if you already own a full license, some of the other license types may still be useful to your office.

Viewer License

The Viewer license is free and is included automatically with every installation. It gives you access to every feature of the software except two: saving and solving.

It’s great as an evaluation tool before buying a new product.

It’s also great for your manager who needs to review your work but doesn’t do the modeling himself. He can open your file, look at all the definition data, explore the results using graphs, contours, exporting data to Excel if necessary, all the tools the software provides. All without spending any money on a license.

Student License

The Student license is also free, and also included in every installation. It is a very “lite” version of the software, intended to help people learn geotechnical engineering concepts, not to perform real engineering analysis.

You can save and solve, but you are restricted to a small mesh, a small number of regions, and so on.

The Student license is most useful as a teaching aid for undergraduate engineering classes.

Basic License

Basic licenses are the most inexpensive licenses we sell–two different options for $995 each.

Like the Student license, they limit access to some of the more advanced features, but are much more powerful than the Student license, and definitely powerful enough to use on the more routine geotech problems you’ll encounter.

There are two Basic licenses in the latest version:

VADOSE/W Basic is a 1-D version of VADOSE/W and CTRAN/W.

GeoStudio Basic is a single license that gives you access to all the products except VADOSE/W. So for a low price you get SLOPE/W, SEEP/W, SIGMA/W, QUAKE/W, TEMP/W, CTRAN/W and AIR/W.

If your firm tends to do more routine analyses, you may want to consider the Basic license.

Full License

The full license, of course, gives you access to all the features of a particular product.

Picking Your License

You choose between those four types of license from the Start Page, before opening or creating a file. In the most recent version the options look like this:

Default template

Choose File – New, select a template, then click “Make this the default template” if you want to use this template all the time.

The default template will be used any time you start a new file by clicking the “New File” button in the toolbar, or by clicking one of the product icons on the Start Page.

The default template should also be the one that is selected initially when you choose File – New from the menu (though that appears to be broken in the current version–I’m hoping we can fix it in the next release).

Creating a New File From the Menu, Toolbar or Start Page

As I alluded to, there are several ways to create a new file, and they all work a bit differently.

Choosing File – New from the menu always shows the box where you get to choose a template, followed by the KeyIn Analyses box. Since the default templates we ship do not contain any analyses, the KeyIn Analyses box is initially empty. If your template does have one or more analyses in it, they will show up in KeyIn Analyses.

Choosing the “New File” button from the toolbar uses the default template. The result is as if you used the menu item, clicked “Create from this template”, selected the default template, then clicked Create.

Clicking one of the product icons on the Start Page (next to the “New” tab) uses the default template and creates a new analysis. The result is as if you clicked the “New File” toolbar button, then created an analysis. So if your default template already has one analysis, you’ll end up with two (the template one and the new one).

Create From Existing

You can use any existing .gsz file as if it were a template. Choose File – New from the menu, then click the “Create From Existing…” button and choose a .gsz.

The .gsz file gets opened but has no name, so when you try to save it you get prompted for a new file name.

The Location of the Templates Folder

The templates listed when you choose File – New are all .gsz files from your Templates folder. The location of the Templates folder can be changed in Tools – Options. One reason you may want to change the location is to share templates with others in the same company–you could create a Templates folder on a shared location on the network.

No Analyses

You may want to create a template with no analyses in it, like the ones that ship with the software. That’s handy if you don’t know what analyses will be used, but you want to set up some common defaults, like default boundary conditions, materials, or units.

To create a template with no analyses, you start out (unintuitively) by creating all the analyses you could possibly want (e.g., one SLOPE/W, one SEEP/W, etc.). That gives you the framework in which you can define the appropriate boundary conditions, materials, and so on. Don’t set any analysis-specific properties like time steps (because our next step is going to be to delete the analyses); only create global objects.

Now delete all the analyses you created. The global objects (boundary conditions, materials) and the file-specific settings (units, scale, extents) will remain, but when you start a new file with this template you’ll have no analyses. As soon as you add an analysis, you’ll see the global objects that apply to it.

Most of us should be familiar with templates. We use them every time we create a fax cover sheet in Word. A Word template is really just a regular Word document but with a different file extension, to avoid repeatedly setting up the same standard titles and styles and boxes.

GeoStudio 2007 ships with two templates, and lets you create your own as well. One of the templates it ships with is a blank document with imperial units already selected (feet, seconds, pounds, etc; under Set Units & Scale); the other is identical except with SI units (meters, seconds, kN, kPa, grams, etc).

In many cases you could benefit by creating your own templates:

If you find yourself always going back into Set Units & Scale and making the same changes.

If you use a different page size (under Set Page).

If you often want to start with a SLOPE/W analysis already created.

If you want everyone in your office to have a standard format with your company name / logo / etc at the bottom of the page.

If you find yourself using the same boundary condition over and over.

Any other repetitive changes you make.

A GeoStudio template is really just a plain old .gsz file saved in a special folder, so anything that normally gets saved in the .gsz can be saved in a template.

Let’s create a simple template today just to demonstrate how it’s done. Say I find myself often doing stability analyses, so I want to just open a template that already has a SLOPE/W analysis, but I always use the Entry and Exit slip surface option instead of Grid and Radius, and I always want to store 10 critical slip surfaces rather than the default of 1.

1. Create a New File

You start just the same as if you were creating a new file. In fact you may want to just take one of your existing files to use as a template.

2. Set Things Up

Remember a template is just another .gsz file, so you set things up just as if you were creating a normal analysis. In my case I’m going to:

Use KeyIn Analyses to add a SLOPE/W Analysis.

On the Slip Surface tab, change the Slip Surface Option to “Entry and Exit”.

On the same tab, change the “No. of critical slip surfaces to store” to “10”.

If I wanted, I could create some common materials I always use, change my page size, problem extents, scale; I could create other analyses, draw a couple of regions, even assign materials to those regions.

3. Give It a Comment

In KeyIn Analyses, select the root item in the tree (labeled “(untitled)”), then describe the template in the Comments field. This description will show up later when you try to use the template (we’ll try that in a minute).

4. Save As Template

This is the step that differentiates this from a normal file. Chose File – Save As Template, and give your template a name, such as “Entry and Exit Slope”

5. Use It

When you want to create a new file from this template, choose File – New, and your template will show up in the list. Notice that when you click on it, the comment you typed at step 3 is displayed to remind you what this template is about.

More Tips

Next week I’ll describe some more concepts around templates. In the meantime, I’d really like to hear how you use templates. Is it something you’ve explored? Do you use them regularly? Did you not even know they were there? Leave your comments or questions and I’ll address them next week as well.

We (engineer) face a problem when we want to define the soil-water characteristic curve. We have no idea what is the maximum suction can develop during the time of analysis, so we normally give up.

I asked Lori, one of our support engineers, if she could address this problem. Lori says:

It’s important to understand that you only need to define the soil-water characteristic curve (also known as the volumetric water content or VWC function) if you are doing a transient analysis. The VWC function describes how water is stored or released due to changes in matric suction or negative pore-water pressure during the transient process.

However, once you have a VWC function defined, you can also use it to estimate the hydraulic conductivity function using established estimation techniques that are built into the GeoStudio software. The hydraulic conductivity function is required for both a steady-state and transient analysis, so often a VWC function is defined regardless of the type of analysis that is being solved.

It’s true that if you expect the negative pore-water pressures to reach a particular value, then the function needs to at least be defined up to this value. However there is a rule of thumb that you can use to determine what this value might be. Unless you are considering evaporation and using a negative flux boundary condition at the ground surface, the maximum negative pore-water pressure that will develop above the phreatic surface will be hydrostatically negative.

To estimate hydrostatic pressures above the phreatic surface, take the maximum distance between the ground surface and the anticipated phreatic surface or P = 0 contour, and multiply it by the unit weight of water (9.807 kN/m^3 or 62.4 pcf).

So if the maximum distance between the phreatic surface and the ground is 10 m, then the maximum negative pressure that would develop would be approximately 100 kPa.

Please note that if you are going to use the volumetric water content function to estimate the hydraulic conductivity function, you will need to ensure that it has been fully defined, from saturation through to residual water content.

There is no problem with defining the water content function over a range that is larger than the anticipated computed negative pore-water pressures. Just make sure you have defined a smooth function that has a nicely defined air-entry value and a smooth transition to a residual water content if necessary.

If you find yourself clicking the “Insert field…” button in Sketch Text several dozen times a day, you may be unaware of a convenient shortcut.

Let’s say, for example, you have several anchors and you want to display the bond length, spacing, resistance and capacity for each. That’s four visits to the “Insert field” dialog box for each anchor. Carpal tunnel problems are not far behind.

To simplify the task, just use Insert field to insert the four fields for one of the anchors.

Then select everything in the box (Ctrl-A), copy it to the clipboard (Ctrl-C), and paste it back in again (Ctrl-V).

Now you need to edit the second group. See where it says “Reinforcements[1]”? You need to change that “1” to a “2”. Instead of clicking on it (which just puts you back in the Insert field box), hold down the Ctrl key while you click. That will position your cursor where you click, so you can now edit the text. (Or you can use the arrow keys to move your cursor into the field name.)

Do the same for any additional anchors, and click on your drawing to position the text just as you normally would.

[Note: While I was trying this out for this blog, I noticed the fields did not always show up as blue underlined text. Normally that would indicate they are not valid fields, but in this case it appears to be a bug. When you insert the text on your drawing, all the fields are interpreted correctly. There’s just something strange going on in the edit box itself. Guess I’d better get back to programming!]

Some of our customers (maybe all? I’m not sure how common this is) keep a huge number of gsz files on their computers.

They may have a large team of people all sharing access to the same files. They save a dozen copies of an analysis, each with a slight difference from the others. One customer described to us how his team uses spreadsheets to keep track of all these files, the differences between them, and who last edited any particular file.

Even if your office doesn’t go to that extreme, you’ll likely still find it useful to store additional information about your analyses that you can refer back to later, or that your manager or co-worker can access to understand what you were trying to do with a particular analysis.

The place to write up those comments is in the file properties.

Use the KeyIn Analyses command, then click on the very root item in the tree, the one that (typically) has the same name as the file.

You’ll notice there’s room there to type in a title, an author (so people know who to go to with questions), and comments. This is where I find it useful to write a short description of the overall project, what I’m trying to achieve with this .gsz file.

You can also write comments for each individual analysis. Still in KeyIn Analyses, click on an analysis in the tree.

At the top-right is a Description field. I use it to describe the purpose of this specific analysis. Often it isn’t really needed–if I have two SEEP/W analyses, the first one steady-state and the second one transient, it’s pretty obvious what I’m doing. But if I have ten SLOPE/W analyses, each identical except for the value of C, the Description field comes in really handy.

When writing comments, it’s best to imagine yourself coming back to this file in a year or two, and having to remember what it is you were doing.

All of those comment fields are visible from the Start Page. Click back on the root item in KeyIn Analyses and then close the dialog box to see the Start Page summarizing the entire file.

If you save the file while you’re at the Start Page, then next time you open it you’ll be put back at the Start Page to quickly see what the file is about.